red dye

基本解释

Mexican red scale insect that feeds on cacti; the source of a red dye.
墨西哥紅色小介殼蟲，喫仙人掌；是紅色染料的原料。
But like a drop of red dye thrown into the ocean, those stars emerged into an enormous object—a galaxy boasting hundreds of billions of other stars.
然而，就像一滴紅色的染料投入了海洋之中，那些恒星已經融入了一個巨大的天躰之中，這就是有著幾千億顆其他恒星的銀河系。
huzhangao.blog.163.com
At this point, the eggs are cooked, the grandmother picked up one of the largest on the use of red paper red dye, and then do a clean cloth, into yard, hanging on my neck.
此時，蛋也煮好了，外婆就撈起一個最大的用紅紙沾水染成了紅色，再用乾佈擦拭乾淨，裝進絡子裡，掛在我脖子上。

When baby seals were being clubbed to death in 1978 in the Magdalene Islands in Canada, the fund's crusaders painted the seals with red dye, making their coats worthless to furriers.
ECONOMIST: Cleveland Amory The
That's exactly what the whiz-kids from the City College of New York, Rice University and the US Army Research Laboratory have done with a new lithium-ion battery powered by red dye extracted from madder roots.
ENGADGET: Scientists develop eco battery powered by root-extracted dye